REMOTE MEMORY MANAGEMENT WHEN SWITCHING OPTICALLY-CONNECTED MEMORY

• US 20130275705A1
• Filed: 02/06/2013
• Published: 10/17/2013
• Est. Priority Date: 04/13/2012
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: SCHENFELD, Eugen, CHAKRABORTY, Abhirup
• Granted Patent: US 9,104,587 B2
• Time in Patent Office: Days
• US Class Current: 711/165
• CPC Class Codes: G06F 12/023 Free address space management
• CPC Class Codes: G06F 12/0284 Multiple user address space allocation, e.g. using different base addresses interprocessor communication G06F15/163
• CPC Class Codes: G06F 12/0292 using tables or multilevel address translation means G06F12/023 takes precedence; address translation in virtual memory systems G06F12/10
• CPC Class Codes: G06F 12/0891 using clearing, invalidating or resetting means
• CPC Class Codes: G06F 12/10 Address translation
• CPC Class Codes: G06F 12/1009 using page tables, e.g. page table structures
• CPC Class Codes: G06F 12/1027 using associative or pseudo-associative address translation means, e.g. translation look-aside buffer [TLB]
• CPC Class Codes: G06F 13/404 with address mapping
• CPC Class Codes: G06F 13/4068 Electrical coupling
• CPC Class Codes: G06F 13/42 Bus transfer protocol, e.g. handshake; Synchronisation
• CPC Class Codes: G06F 2212/50 Control mechanisms for virtual memory, cache or TLB
• CPC Class Codes: G06F 2212/60 Details of cache memory
• CPC Class Codes: G06F 2212/683 Invalidation
• CPC Class Codes: G06F 3/0604 Improving or facilitating administration, e.g. storage management
• CPC Class Codes: G06F 3/0631 by allocating resources to storage systems
• CPC Class Codes: G06F 3/0647 Migration mechanisms
• CPC Class Codes: G06F 3/067 Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS]

Abstract

A remote memory superpage is retained in a remote memory of the memory blade when reading the remote memory super page of the remote memory into a local memory.

Claims

1. In an optically-connected memory (OCM) system, a method for remote memory management, comprising:

retaining a remote memory superpage in a remote memory of a memory blade when reading the remote memory super page of the remote memory into a local memory.

2. The method of claim 1, further including performing the retaining on a side of a source node.

3. The method of claim 1, wherein the optically-connected memory (OCM) system includes a plurality of processors arranged in processor blades and memory in memory blades, with each of the processor blades and the memory blades organized in racks communicatively coupled through an optical-switching fabric, the processor blades and the memory blades remotely separated.

4. The method of claim 3, further including performing the retaining upon dynamically switching the memory through the optical-switching fabric using a selected one of a plurality of available communication patterns to transfer a remote machine memory address (RMMA) space in the memory blades from one of the plurality of processors to an alternative one of the plurality of processors in the processor blades without physically copying data in the memory to the plurality of processors.

5. The method of claim 3, further including writing back the remote memory super page onto the remote memory while being evicted from the local memory if the remote memory superpage is deleted upon a read operation.

6. The method of claim 3, further including removing the remote memory super page from the local memory if the remote memory super page is not dirty when retaining the remote memory superpage in the remote memory, wherein back pressure on the optical channel bandwidth is saved.

7. The method of claim 6, further including if the remote memory super page is dirty, sending only a changed portion of the remote memory super page to the local memory using a delta coding

8. The method of claim 3, further including determining whether to retain or remove the remote memory super page in the remote memory based on an update pattern of the remote memory super page.

9. The method of claim 3, further including:

supplying a set of remote memory superpages by an optical plane, and

assimilating the remote memory superpages by grafting the remote memory superpages into a system memory address (SMA) space of the remote processor for creating a mapping within the page table.

10. The method of claim 3, further including distinguishing ranges of a remote machine memory address (RMMA) space that are overlapping based on one of a channel identification (ID) and a blade ID.

11. The method of claim 3, further including:

allocating memory from one of the memory blades upon receiving a memory request from the one of the plurality of processors, wherein a circuit is established with the memory for the one of the plurality of processors, a remote machine memory address (RMMA) space of the memory sent to the one of the plurality of processors, and

transferring a physical memory address space from the one of the processors to the alternative one of the plurality of processors.

12. The method of claim 3, further including performing:

sending the meta data and a switching request to the one of the plurality of processors,

adjusting a remote machine memory address (RMMA) space and flushing a translation look-aside buffer (TLB),

performing an unmapping operation for removing entries in page tables that map a linear address to the RMMA space,

dynamically switching the memory from an active node of the one of the plurality of processors to a remote active node of the alternative one of the plurality of processors, and

using the page tables by the remote processor for instantaneous access to the data.

13. An optically-connected memory (OCM) system for remote memory management, comprising:

at least one processor device operable in the computing storage environment, wherein the at least one processor device;

retains a remote memory superpage in a remote memory of a memory blade when reading the remote memory super page of the remote memory into a local memory.

14. The system of claim 13, further including:

a plurality of nodes, in communication with the at least one processor device, including at least a source node, passive nodes, and receiving nodes,

at least one processor blade,

at least one memory blade, remotely separated from the at least one processor blade,

an optical plane,

the least one processor device arranged in one of the at least one processor blade and the at least one memory blade and in communication with the optical plane,

a translation look-aside buffer (TLB) in communication with the at least one processor device and the optical plane,

at least one memory in the at least one memory blade, and

an optical switching fabric communicatively coupled between the at least one processor blade and the at least one memory blade and in communication with the at least one processor device.

15. The system of claim 14, wherein the at least one processor device performs the collecting, the extracting, and the unmapping on a side of the source node.

16. The system of claim 14, wherein the at least one processor device performs the retaining while dynamically switching the memory through the optical-switching fabric using a selected one of a plurality of available communication patterns to transfer a remote machine memory address (RMMA) space in the memory blades from one of the plurality of processors to an alternative one of the plurality of processors in the processor blades without physically copying data in the memory to the plurality of processors.

17. The system of claim 14, wherein the at least one processor device writes back the remote memory super page onto the remote memory while being evicted from the local memory if the remote memory superpage is deleted upon a read operation.

18. The system of claim 14, wherein the at least one processor device removes the remote memory super page from the local memory if the remote memory super page is not dirty when retaining the remote memory superpage in the remote memory, wherein back pressure on the optical channel bandwidth is saved.

19. The system of claim 18, wherein the at least one processor device, if the remote memory super page is dirty, sends only a changed portion of the remote memory super page to the local memory using a delta coding

20. The system of claim 14, wherein the at least one processor device determines whether to retain or remove the remote memory super page in the remote memory based on an update pattern of the remote memory super page.

21. The system of claim 14, wherein the at least one processor device:

supplies a set of remote memory superpages by an optical plane, and

assimilates the remote memory superpages by grafting the remote memory superpages into a system memory address (SMA) space of the remote processor for creating a mapping within the page table.

22. The system of claim 14, wherein the at least one processor device distinguishes ranges of a remote machine memory address (RMMA) space that are overlapping based on one of a channel identification (ID) and a blade ID.

23. The system of claim 14, wherein the at least one processor device:

allocates memory from one of the memory blades upon receiving a memory request from the one of the plurality of processors, wherein a circuit is established with the memory for the one of the plurality of processors, a remote machine memory address (RMMA) space of the memory sent to the one of the plurality of processors, and

transfers a physical memory address space from the one of the processors to the alternative one of the plurality of processors.

24. The system of claim 14, further including page tables, wherein the at least one processor device:

sends the meta data and a switching request to the one of the plurality of processors,

adjusts a remote machine memory address (RMMA) space and flushing a translation look-aside buffer (TLB),

performs an unmapping operation for removing entries in the page tables that map a linear address to the RMMA space,

dynamically switches the memory from an active node of the one of the plurality of processors to a remote active node of the alternative one of the plurality of processors, and

uses the page tables by the remote processor for instantaneous access to the data.

25. In an optically-connected memory (OCM) system, for remote memory management, a computer program product in a computing environment using a processor device, the computer program product comprising a computer-readable storage medium having computer-readable program code portions stored therein, the computer-readable program code portions comprising:

a first executable portion that retains a remote memory superpage in a remote memory of a memory blade when reading the remote memory super page of the remote memory into a local memory.

26. The computer program product of claim 25, wherein the optically-connected memory (OCM) system includes a plurality of processors arranged in processor blades and memory in memory blades, with each of the processor blades and the memory blades organized in racks communicatively coupled through an optical-switching fabric, the processor blades and the memory blades remotely separated.

27. The computer program product of claim 26, further including a fourth executable portion that performs the retaining on a side of a source node:

28. The computer program product of claim 26, further including a second executable portion that performs the retaining upon dynamically switching the memory through the optical-switching fabric using a selected one of a plurality of available communication patterns to transfer a remote machine memory address (RMMA) space in the memory blades from one of the plurality of processors to an alternative one of the plurality of processors in the processor blades without physically copying data in the memory to the plurality of processors.

29. The computer program product of claim 26, further including a second executable portion that writes back the remote memory super page onto the remote memory while being evicted from the local memory if the remote memory superpage is deleted upon a read operation.

30. The computer program product of claim 26, further including a second executable portion that removes the remote memory super page from the local memory if the remote memory super page is not dirty when retaining the remote memory superpage in the remote memory, wherein back pressure on the optical channel bandwidth is saved.

31. The computer program product of claim 30, further including a third executable portion that, if the remote memory super page is dirty, sends only a changed portion of the remote memory super page to the local memory using a delta coding

32. The computer program product of claim 26, further including a second executable portion that determines whether to retain or remove the remote memory super page in the remote memory based on an update pattern of the remote memory super page.

33. The computer program product of claim 26, further including a second executable portion that:

supplies a set of remote memory superpages by an optical plane, and

assimilates the remote memory superpages by grafting the remote memory superpages into a system memory address (SMA) space of the remote processor for creating a mapping within the page table.

34. The computer program product of claim 26, further including a second executable portion that distinguishes ranges of remote machine memory address (RMMA) that are overlapping based on one of a channel identification (ID) and a blade ID.

35. The computer program product of claim 26, further including a second executable portion that:

allocates memory from one of the memory blades upon receiving a memory request from the one of the plurality of processors, wherein a circuit is established with the memory for the one of the plurality of processors, a remote machine memory address (RMMA) of the memory sent to the one of the plurality of processors,

retains a remote memory superpage of the memory in the memory blade when reading the remote memory super page of the memory into the one of the plurality of processors, and

transfers a physical memory address space from the one of the processors to the alternative one of the plurality of processors.

36. The computer program product of claim 26, further including a second executable portion that:

sends the meta data and a switching request to the one of the plurality of processors,

adjusts a remote machine memory address (RMMA) and flushing a translation look-aside buffer (TLB),

performs an unmapping operation for removing entries in the page tables that map a linear address to the RMMA space,

dynamically switches the memory from an active node of the one of the plurality of processors to a remote active node of the alternative one of the plurality of processors, and

uses the page tables by the remote processor for instantaneous access to the data.